Card cages are known which comprise a framework within which a plurality of circuit panels or daughter cards are insertable, and within which is disposed a backplane transverse to the back edges of the daughter cards. The cards are electrically connected to the backplane by any of several types of known connectors and terminals, and are interconnected by the backplane to each other and to other electrical components on the opposite side of the backplane. Each daughter card in conventional card cages also receives all necessary power for its components from the backplane through a plurality of terminals. One typical method involves providing a multilayer backplane having power-carrying circuit paths embedded within it, involving significant fabrication expense, to which terminals are engaged to transmit the power current at levels ordinarily about one ampere per terminal through connectors to the daughter card. Connectors which must house the quite numerous power-carrying terminals also must house signal terminals for the primary purpose of providing signal transmission to and from the daughter cards; signal terminals are thus limited in number and in their position, which in turn limits the capabilities of the daughter cards. Also, the current levels presently available limit the number and types of components usable with the daughter cards.
Another feature of conventional card cages is that the power is provided to the backplane from power conductor cables from outside the card cage, and the transmission of power into the card cage is usually controlled by one switch. In such card cages transmission of power to the individual daughter cards is not controlled on a card-by-card basis and in fact power to all the cards is either all ON or all OFF. Therefore, power to all cards must be turned off to permit insertion or removal of an individual daughter card, resulting in undesirable levels of down time.
Multilayering of daughter cards is presently done to transmit power received along the back edge by numerous power terminals, to interior regions of the daughter card in order to avoid interfering with the increasing number and the positioning of signal circuit paths desired, in an effort to enhance the capabilities of daughter cards, given the limitation of back edge power reception in present day card cages. Multilayering of daughter cards, as with multilayering of backplanes, is costly.
It would be desirable to provide power to daughter cards of a card cage individually, and to shut off power individually.
It would be desirable to introduce the power to the daughter cards along edge surfaces other than along the back edge, thus allowing the connectors along the back edge to be devoted to signal transmission and increase the number of signal transmission connections to the backplane.
It would be desirable to provide power at current levels higher than is presently available to individual power paths of the daughter card, and to provide a higher total power current to the card.
It would also be desirable to provide power at current levels of ten amperes or higher, from active or power-receiving edge portions into the interior regions of the card without the necessity of using etched circuit paths or multilayer circuit panel construction.